got a advisory on the MOT today that the rear springs are coroded badly.

Does anybody know a good supplier for some new ones wouldnt mind some uprated ones but all I can find is lowering springs which I dont want, too many speed bumps round me.

You could try Steve at alternative autos?

OSRAV do a spring for the coupe that is uprated and only very slightly lowers the car.
Your usual uprated spring will lower it by 2.5 to 3cm so shouldn't be an issue with speed bumps.